Process for the conversion of textile vegetable fibers into threads having the texture of wool



Patented Aug. 8, 1933 UNITED, STATES PATENT OFFICE TEXTILE VEGETABLE FIBERS THREADS WOOL INTO HAVING THE TEXTURE OF Frederic Georges Maillard, Paris, France No Drawing. Application May 23, 1929, vSerial No. 365,566, and in France April 18, 1929.

Renewed May 8 1933 3 Claims.

This invention relates to an improved process for the conversion of vegetable fibers of the lignocellulose class, such as jute, hemp and the like, into a wool-substitute, which comprises submitting the fibers to a mechanical treatment in a greasy bath, then spinning them into thread and doubling, next treating said thread, for the purpose of separating the ligneous from the cellulose constituents, first in a bath of alkali metal carbonate and then with a mixture of sodium sulphoricinate and alkaline carbonate, next chemically converting the ligneous constituents by hydrolizing in a bath of caustic alkali, and finally bleaching, finishing and rendering the threads impermeable.

After a mechanical treatment in a greasy bath, containing seven per cent of completely saponifiable wool-oil, followed by carding and drawing, the fibers are spun into threads by the customary mechanical means and are doubled.

The threads are then chemically treated, for the purpose of separating the ligneous from the cellulose constituents, first by soaking them in a bath of an alkaline carbonate at a temperature of 60 C.; and secondly in sodium sulphoricinate, to .which an alkali metal carbonate is added, at the ordinary temperature. These two chemical treatments are carried out in a vacuum and their duration as well as the degree of concentration of the baths may vary and must be determined according to the degree of fineness, which it is desired to obtain.

The threads after being removed from the baths above mentioned are thoroughly washed in water to remove all traces of the reagents used and dried.

They are then submitted, still in a vacuum, to a chemical conversion of the ligeous constituents by hydrolizing in a bath of concentrated caustic alkali at the ordinary temperature; this is followed by neutralizing with acid and washing.

The final stages of bleaching, finishing and rendering the threads impermeable comprise a preliminary bleaching by slight chloring or by permanganate and bisulphite, followed by washing and a further bleaching by passing the threads through a mixture of sulphurous and sulphuric acid gases obtained by the combustion of sulphur in a furnace, the proportion of sulphuric acid gas being from five to ten per cent of the mixture.

The threads are then finished by neutralizing in an alkaline and sulphoricinate bath and again washing.

Finally the threads are rendered impermeable by an electrolytic treatment in a bath of aluminium sulpho-acetate, and are dried at a low temperature For the better elucidation of the process the following detailed example may be given.

The raw material, which may be jute or hemp, is stacked in a greasy bath, containing about seven per cent of completely saponifiable wool-oil, in superposed layers and left at rest for five to seven days, for the purpose of bringing the vegetable fibers approximately to the desired degree of fineness and suppleness as well as of removing adherent extraneous matter. The greasy bath contains seven per cent of completely saponifiable wool-oil and the fibers take up about twenty per cent of their own weight.

The fibers are then passed through a carding engine and drawing frame so as to straighten them as far as possible and are then spun into threads and doubled.

The threads thus obtained are treated for the purpose of separating the ligneous from the cellulose constituents, which is done by first soaking them in a bath of an alkali metal carbonate being five per cent by weight of the threads; and secondly by sodium sulphoricinate to which there isadded an alkali metal carbonate (10 granmie's per litre) at the ordinary temperature for half an hour; these two treatments are carried out in a vacuum; after which the threads are thoroughly washed and dried in a hydro-extractor.

The next step is the chemical conversion of the ligneous constituents in a bath of concentrated caustic alkali, the degree of concentration ranging from 18 to 25 Baum according to the nature of the fibers treated. This treatment is carried out at the ordinary temperature and on the average takes half an hour. It is followed by draining, neutralizing with acid and washmg.

The following step comprises the bleaching and finishing of the threads. A preliminary bleaching is done by chloring at half a chlorometric degree, followed by washing, acidifying and rewashing or by passing the threads through permanganate and bisulphite followed by washing. The bleaching is completed by passing the threads through a mixture of sulphurous and sulphuric acid gases, the latter being about five to ten per cent of the mixture, and the gases being obtained by the combustion of sulphur in a furnace kept at a temperature of C. The finishing is effected by impregnating the threads in a ten per cent alkaline sulphoricinate bath, which neutralizes them and renders the threads more supple and softer to the touch.

The final step is to render the threads impermeable, which is done by an alkaline sulphoricinate converted into aluminium sulphoricinate as jute, hemp and the like, into a wool-substitute, which comprises submitting the fibers to a mechanical treatment in a greasy bath, then spinning them into thread and doubling, next treating said thread, for the purpose of separating the ligneous from the cellulose constituents, first in a bath of alkali metal carbonate and then with a mixture of sodium sulphorlcinate and alkaline carbonate, next chemically converting the ligneous constituents by hydrolizing in a bath of caustic alkali and finally bleaching, finishing and rendering the threads impermeable.

2. In a process as claimed in claim 1 the separation of the ligneous from the cellulose constituents, in a bath containing an alkali metal carbonate to the amount of five per cent of the weight of the threads treated and kept at a temperature of about 60 C.

3. In a process as claimed in claim 1, the caustic alkali bath employed for the modification of the nature and structure of the material treated has a concentration of 18 to 25 Baum according to the nature of the threads.

FREDERIC GEORGES MAILLARD. 

